An LED device or an LED, as used herein, is a semiconductor light source for generating a light at a specified wavelength or a range of wavelengths. LEDs have increasingly gained popularity due to favorable characteristics such as small device size, long lifetime, efficient energy consumption, and good durability and reliability. In recent years, LEDs have been deployed in various applications, including indicators, light sensors, traffic lights, broadband data transmission, and illumination devices. LEDs emit light when a voltage is applied.
LEDs may be made by growing a plurality of light-emitting structures on a growth substrate. The light-emitting structures along with the underlying growth substrate are separated into individual LED dies. At some point before or after the separation, electrodes or conductive pads are added to the each of the LED dies to allow the conduction of electricity across the structure. The light-emitting structure and the wafer on which the light-emitting structure is formed are referred to herein as an epi wafer. LED dies are then packaged by adding a package substrate, optional phosphor material, and optics such as lens and reflectors to become an optical emitter.
LEDs typically include doped III-V compound layers. Traditional methods of forming such doped III-V compound layers may result in degraded LED performance, such as low light output power, low carrier mobility, and excessively high contact resistance or sheet resistance.
Therefore, while existing methods of manufacturing the LEDs have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect. A better method of forming doped III-V compound layers for LEDs continues to be sought.